Intraocular lenses

ABSTRACT

An intraocular lens with a medial light-focusing lens body includes oppositely disposed position fixation means with respective seating portions that are resiliently retained in the eye without sutures. One of the position fixation means is adapted to be seated forwardly of the other position fixation means with respect to the optical axis of the eye. After the intraocular lens has been inserted in the eye the seating portion of the forwardly disposed position fixation means has a greater radial extent from the optical axis of the eye than the seating portion of the rearwardly disposed position fixation member.

This invention relates to intraocular lenses for the human eye and moreparticularly to an intraocular lens having one support member that isseated forwardly of another support member in the eye.

The placement or insertion of an intraocular lens in the eye is a wellknown and widely used technique for restoring vision after a cataractremoval operation. The natural structure of the eye furnishes a varietyof locations for fixing the position of an intraocular lens in the eye.For example, an intraocular lens can be supported anteriorly of the irisbetween the scleral spur and the iris as disclosed in my patentapplication Ser. No. 911,452 filed June 1, 1978, now U.S. Pat. No.4,174,543. Alternatively, an intraocular lens can be supportedposteriorly of the iris between the anterior and posterior capsule wallsas disclosed in my U.S. Pat. No. 4,092,743.

It is often desirable to support the intraocular lens posteriorly of theiris between the anterior and posterior capsule walls, preferablywithout suturing. However, such positioning cannot always be achievedbecause the extent of anterior wall structure at the upper portion ofthe eye that remains after cataract surgery is usually insufficient toaccommodate and hold a position fixation member of the intraocular lenswithout suturing. Therefore since suturing might be necessary to securethe position fixation member to the upper anterior capsule wall of theeye other locations in the eye which do not require sutures are likelyto be considered.

It has been found that a posterior chamber, two-loop intraocular lenssuch as Model PC-10 made by Heyer-Schulte Medical Optics Center ofIrvine, California, can be positioned without sutures in the ciliarysulcus of the eye between the iris and the anterior capsule wall. Theposterior chamber, two-loop intraocular lens comprises a mediallight-focusing lens body with a pair of oppositely disposed,dimensionally equivalent position fixation members in the general shapeof a J. The J-shaped position fixation members are usually formed of aplastic such as polypropylene having sufficient spring-like quality toprovide a resilient locking of the lens body in the ciliary sulcus ofthe eye. Although resilient contact of the position fixation members inthe ciliary sulcus provides stable positioning of the lens body in theeye without sutures, the total force exerted by the position fixationmembers on the ciliary sulcus may in some instances reach an undesirablelevel.

The known posterior chamber two-loop intraocular lens, after insertionin an eye, may require further adjustments of the position fixationmembers to achieve optimum positioning of the lens body. Often anadjustment need only be made to one of the position fixation members.However, because the ciliary sulcus is not as accessible as otherregions of the eye it is difficult to ascertain which of the positionfixation members require further adjustment. Therefore, it is usuallynecessary to check, adjust, and readjust each of the position fixationmembers as assurance that optimum positioning of the posterior chamber,two-loop intraocular lens has been accomplished.

It is thus desirable to provide an intraocular lens which can bepositioned in the eye posteriorly of the iris without suturing, withrelatively easy adjustment, and which will minimize the overall force onthe ciliary sulcus.

Among the several objects of the present invention may be noted theprovision of an intraocular lens having two oppositely disposed positionfixation members, one of which is adapted to be resiliently retained inthe ciliary sulcus and the other of which is adapted to be resilientlyretained between the anterior and posterior capsule walls, and anintraocular lens which imposes substantially less force on the ciliarysulcus than the posterior chamber, two-loop intraocular lens.

Other objects and features will be in part apparent and in part pointedout hereinafter.

The present invention relates to a novel intraocular lens having a lensbody with two oppositely disposed position fixation members, one of theposition fixation members having means for permitting it to be seated inthe eye forwardly of the other position fixation member with respect tothe optical axis of the eye. To facilitate description of the structuredisclosed herein it will be presumed that the eye has an optical axispassing through the center of the pupil. It will also be presumed thatwhen the intraocular lens is inserted in an optimum position in the eyethe optical axis of the lens body substantially aligns with the opticalaxis of the eye.

In an average human eye the distance from the optical axis of the eye tothe inner peripheral surface of the ciliary sulcus is approximately oneto two millimeters greater than the distance from the optical axis tothe inner peripheral surface of a circumferential cul-de-sac portion ofthe eye between the anterior and posterior capsule walls.

In one embodiment of the invention the seating portions of each positionfixation member are substantially equidistant from the optical axis ofthe lens body but the deflective stiffness of the position fixationmembers is different. Thus when equal forces are presented against theseating portions of each position fixation member the softer member willdeflect a greater amount than the stiffer member. The stiffer member canthus be seated in the ciliary sulcus for example, and the softer membercan be seated rearwardly of the stiffer member in the circumferentialcul-de-sac portion of the eye formed between the anterior and posteriorcapsule walls. The softer position fixation member is thus structured todeflect approximately one to two millimeters more than the stifferposition fixation member under equal force conditions. The seatingportions of the position fixation members can have a generally coplanararrangement with the lens body. Therefore, when one position fixationmember is seated forwardly of the other, the lens body is tiltedslightly with respect to the pupil of the eye. Such inclination isacceptable since it is approximately 10° from the vertical.

In another embodiment of the invention the seating portion of oneposition fixation member is approximately one to two millimeters lessdistant from the optical axis of the lens body than the seating portionof the other position fixation member and the deflective stiffness ofthe position fixation members is substantially equivalent. As with theprevious embodiment the seating portions of the position fixationmembers can have a generally coplanar arrangement which leads to aslight tilt of the lens body with respect to the pupil of the eye.

In another embodiment of the invention the seating portion of oneposition fixation member is also approximately one to two millimetersless distant from the optical axis of the lens body than the seatingportion of the other position fixation member. The deflective stiffnessof the position fixation members is substantially equivalent but one ofthe position fixation members is inclined with respect to the lens bodyso that its seating portion is offset forwardly from the seating portionof the other position fixation member approximately seven to twelvedegrees. The offset between the seating portions enables the lens bodyto be substantially uninclined with respect to the pupil of the eyeafter insertion of the intraocular lens in the eye.

In a further embodiment of the invention the position fixation membershave substantially equivalent deflective stiffness and the respectiveseating portions have a one to two millimeter difference in extent fromthe optical axis of the lens body. However, one of the position fixationmembers is formed with a step to provide an offset of its seatingportion from the seating portion of the other position fixation member.The offset thus enables the lens body of the inserted intraocular lensto be substantially free of inclination with respect to the pupil of theeye.

In each of the embodiments of the intraocular insert the positionfixation members are preferably integrally joined to the lens body. Thelens body and the integrally joined position fixation members areinserted in the eye through a corneo-scleral incision for example, andthe stiffer position fixation member or the one having the more remotelydisposed seating portion with respect to the optical axis of the lensbody is seated in the ciliary sulcus of the eye whereas the seatingportion of the other position fixation member is seated in thecircumferential cul-de-sac portion of the eye between the anterior andposterior capsule walls. The resilient spring-like characteristics ofthe position fixation members enables the intraocular lens to bemaintained in position without suturing due to the resilient contact ofone position fixation member against the ciliary sulcus, and theresilient contact of the other position fixation member against thecircumferential cul-de-sac portion between the anterior and posteriorcapsule wall surfaces.

Since only one of the position fixation members is disposed in theciliary succus region of the eye there is less total force on thisregion after the intraocular lens has been inserted than that providedby the known posterior chamber, two-loop intraocular lens. Placement ofone of the position fixation members in the circumferential cul-de-sacportion of the eye between the anterior and posterior capsule walls alsofacilitates positioning of the other position fixation member in theciliary succus region.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawing in which various embodiments of theinvention are illustrated,

FIG. 1 is a simplified plan view of an intraocular insert incorporatingone embodiment of the present invention;

FIG. 2 is a simplified schematic sectional view of an eyeball with theintraocular insert seated therein;

FIG. 3 is representative of the prior art;

FIG. 4 is a simplified front view of the insert in an eye, lookingposteriorly of the iris; and,

FIGS. 5 and 6 are simplified plan views of other embodiments of theinvention.

Referring now to the drawing, an intraocular insert incorporating oneembodiment of the invention is generally indicated by reference number10 in FIG. 1.

The intraocular insert includes a medial light-focusing lens body 12having a convex or flat anterior surface 14 and a generally flat orconvex posterior surface 16. A pair of position fixation members 18 and20 are integrally joined to opposite peripheral sections 22 and 24 ofthe lens body 12.

The position fixation members 18 and 20 are preferably of J-shapedconfiguration. The position fixation member 18 has a leg portion 26extending from the peripheral section 22 and terminates in a curvedseating portion 28. The position fixation member 20 has a leg portion 30extending from the peripheral section 24 and terminates in a curvedseating portion 32.

The lens body 12 and the position fixation members 18 and 20 are formedof any suitable material which is compatible with the environment at theinterior of the eyeball, such as a non-toxic plastic, for examplepolypropylene.

Referring to FIG. 2, the intraocular insert 10 is inserted in an eyeball34 using suitable known medical procedures, which include, for example,a corneo-scleral incision 36. Insertion of the intraocular insert 10 ispreferably accomplished by orienting the lens body 12 so that one andonly one of the position fixation members 18 and 20 enters the incision36 before insertion of the other position fixation member.

For example, although the intermediate steps of insertion of theintraocular insert 10 are not shown, the position fixation member 20first enters the incision 36 followed by entry of the lens body 12 andthereafter entry of the position fixation member 18.

The lens body 12 has an optical axis 38, which for the sake ofsimplicity is presumed to be the geometric center of the lens body. Itwill also be presumed that the eye has an optical axis 40 passingthrough the center of the pupil located between the iris 42. The eyeball34 includes an anterior capsule wall 44 that has been partially removedwith the cataract as shown in FIGS. 2 and 4, and a posterior capsulewall 46. It should be noted that after a cataract removal the upperportion of the eye usually has a lesser amount of anterior capsule wall44 than does the lower portion.

A ciliary sulcus portion 48 of the eye is defined between the iris 42and the anterior capsule wall 44. The ciliary sulcus 48 extendscircumferentially at upper and lower portions of the eye when viewed incross-section.

A circumferential cul-de-sac portion 50 of the eye is defined betweenthe anterior capsule wall 40 and the posterior capsule wall 46, at upperand lower portions of the eye when viewed in cross-section as shown inFIGS. 2 and 3. The ciliary sulcus 48 and the circumferential cul-de-sacportion 50 are thus interior peripheral surfaces of the eye 34. Theinterior surface of the ciliary sulcus 48 is approximately 1 to 2millimeters further away from the optical axis of the eye than theinterior peripheral surface of the circumferential cul-de-sac portion50.

In the embodiment of the intraocular insert shown in FIG. 1, the seatingportions 28 and 32 of the position fixation members 18 and 20 aresubstantially equidistant from the optical axis 38 of the lens body 12.Furthermore, the radial distance of the seating portions 28 and 32 fromthe optical axis of the lens body 12 is normally greater than thedistance between the optical axis of the eye and the interior peripheralsurface of the ciliary sulcus 48. However, the cross-section of theposition fixation member 20 is less than that of the position fixationmember 18 by a predetermined amount so as to enable the seating portion32 to deflect 1 to 2 millimeters more than the seating portion 28 undera predetermined given force condition.

When the intraocular insert 10 is inserted into the eye, the seatingportions 28 and 32 are deflected toward the optical axis of the eye butrespectively resiliently bear against the ciliary sulcus 48 and thecircumferential cul-de-sac 50. The predetermined force conditionpreviously referred to is thus the force imposed by the ciliary sulcus48 and the circumferential cul-de-sac 50 on the respective seatingportions 28 and 32. Since the seating portion 32 deflects 1 to 2millimeters more than the seating portion 28, the seating portion 32 canbe disposed in the circumferential cul-de-sac 50 whereas the seatingportion 28 can be disposed in the ciliary sulcus 48. As the seatingportions 28 and 32 are generally coplanar, in a plane which is parallelto the posterior surface 16 of the lens body 12, the lens body 12 isinclined approximately 10° with respect to the vertical, which is withinacceptable limits.

Preferably the position fixation members 18 and 20 are formed of thesame material. However, this invention also contemplates the use ofdifferent materials for the position fixation members, wherein onematerial is less stiff than the other, the respective stiffnesses beingpredetermined to ensure that the seating portion 32 deflects 1 to 2millimeters more toward the optical axis of the eye than the seatingportion 28 under force conditions such as are present in the eye whenthe intraocular insert 10 is positioned as indicated in FIG. 2.

The dimensions of the various components of the intraocular lens 10 aresimilar to those of the model PC-10, posterior chamber, two loopintraocular lens made by Heyer-Schulte, previously referred to, exceptfor the structural modifications that can be made by persons skilled inthe art to accomplish the difference in deflection magnitudes of therespective seating portions 28 and 32 for the given force conditionsimposed by the eye on the seating portions.

In another embodiment of the invention, which is also illustrated by theintraocular lens shown in FIG. 2, the seating portion 32 of the positionfixation member 20 is formed 1 to 2 millimeters closer to the opticalaxis of the lens body 12 than the seating portion 28 of the positionfixation member 18. The position fixation members 18 and 20 areotherwise formed of the same material and have identical cross-sectionaldimensions.

Upon insertion of the intraocular lens in the eye, the position fixationmembers 18 and 20 are seated as shown in FIG. 2. Since the seatingportion 32 of the position fixation member 20 is closer to the opticalaxis of the lens body than the seating portion 28 of the positionfixation member 18, the seating portion 32 can be accommodated in thecircumferential cul-de-sac portion 50 whereas the seating portion 28 canbe accommodated in the ciliary sulcus 48. The seating portions 28 and 32deflect equivalent amounts under a given force condition to permitresilient retention of the position fixation member in their respectivelocations in the eye. As with the embodiment previously described, theseating portions 28 and 32 are substantially coplanar resulting in aslight inclination of the lens body with respect to the vertical.

In another embodiment of my invention, an intraocular insert isgenerally indicated by the reference number 60 in FIG. 5. Theintraocular insert 60 includes a lens body 62 corresponding to the lensbody 12, and position fixation members 64 and 66 corresponding to theposition fixation members 18 and 20. The position fixation member 64includes a seating portion 68 and the position fixation member 66includes a seating portion 70. The seating portion 70 is approximately 1to 2 millimeters closer to the optical axis 38 of the lens body 62 thanthe seating portion 68 of the position fixation member 64. However, theposition fixation member 64 includes a stepped portion 72 which providesa forward offset of the seating portion 68 from the seating portion 70with respect to the optical axis 38 of the lens body 62. The offset 72is predetermined so as to enable the lens body 62 to remainsubstantially vertically disposed in the eye when the seating portion 68is seated in the ciliary sulcus 48 and the seating portion 70 is seatedin the circumferential cul-de-sac portion 50 of the eye.

In a further embodiment of my invention as shown in FIG. 6, anintraocular lens is generally indicated by the reference number 80. Theintraocular lens 80 includes a lens body 82 having a position fixationmember 84 corresponding to the position fixation member 18 and aposition fixation member 86 identical to the position fixation member66. The position fixation member 84 is inclined a predetermined amountfrom the vertical approximately seven to twelve degrees, such that aseating portion 88 is forwardly disposed from a seating portion 90 onthe position fixation member 86 by an amount that is substantiallyequivalent to the axial distance between the ciliary sulcus 48 and thecircumferential cul-de-sac portion 50 of the eye. The seating portion 90of the position fixation member 86 is 1 to 2 millimeters closer to theoptical axis 38 of the lens body 82 than is the seating portion 88 ofthe position fixation member 84. The position fixation members 84 and 86have similar cross-sections and their respective seating portions 88 and90 deflect substantially equal amounts when subjected to a given force.The intraocular insert 80 is inserted in the eye with the seatingportion 88 accommodated by the ciliary sulcus 48 and the seating portion90 accommodated by the circumferential cul-de-sac portion 50 of the eye.Because of the inclination of the position fixation member 84, the lensbody 82 has substantially no inclination with respect to the verticaland there is minimal chafing of the iris by the position fixation member84.

In each of the embodiments of the invention, only one of the positionfixation members is seated in the ciliary sulcus 48 of the eye.Therefore, there is less total force on this region than would be feltif both of the position fixation members were resiliently seated in theciliary sulcus region 48 as shown by the intraocular insert 100 in FIG.3.

The prior art intraocular insert 100 includes a lens body 102, aposition fixation member 104 and a position fixation member 106 havingrespective seating portions 108 and 110. The seating portions 108 and110 are normally equidistant from an optical axis 40 of the lens body102, and their respective position fixation members have identicalcross-sections. The seating portions 108 and 110 of the intraocularinsert 100 are resiliently located in upper and lower portions of theciliary succus region 48 of the eye. However it is not feasible toposition the seating portion 110 in the circumferential cul-de-sacportion 50 of the eye because of intolerable forces that woule arise dueto the increased deflection requirements for accommodation in thecircumferential cul-de-sac portion 50.

While the invention has been disclosed with the position fixation member18 disposed in the upper portion of the ciliary succus 48, it iscontemplated that such orientation can be reversed with the positionfixation member 18 disposed in the lower portion of the ciliary sulcus.It is also contemplated that with respect to the embodiment 60 theposition fixation member 64 can be free of any step and that theposition fixation member 66 can have a step that would likewise assurevertical disposition of the lens body 62 with respect to the opticalaxis 40 of the eye. It is also contemplated with respect to theembodiment 80 of FIG. 6 that the position fixation member 86 be inclinedand that the position fixation member 84 be uninclined to assurevertical disposition of the lens body 82 with respect to the opticalaxis 40 of the eye.

As will be apparent to those skilled in the art, the position fixationmember which is disposed in the ciliary sulcus at the upper portion ofthe eye can also be disposed in the ciliary sulcus at the lower portionof the eye and the position fixation member which is seated in thecircumferential cul-de-sac portion 50 at the lower portion of the eyecan be seated in the circumferential cul-de-sac portion 50 at the upperportion of the eye. It is contemplated that the seating portion of onefixation member can have a smaller radius of curvature than that of theother position fixation member to permit viewing behind or positioningthru an iridectomy the position fixation member having the smallerradius of curvature.

Some advantages of the present invention evident from the foregoingdescription include an intraocular insert which can be resilientlyretained in the eye without exerting undesirable force on the ciliarysulcus of the eye, and an intraocular insert that can be relativelyeasily adjusted in the eye because only one of the position fixationmembers is seated in the ciliary sulcus portion of the eye.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes can be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawing should be interpreted as illustrative and not in a limitingsense.

What is claimed is:
 1. An intraocular insert suitable for use as anartificial lens in the interior of a human eye, said eye interior havingupper and lower portions and including a pupil, an iris and an anteriorcapsule wall with a ciliary sulcus defined between said iris and saidanterior capsule wall, said ciliary sulcus comprising a first interiorperipheral surface extending circumferentially at said upper and lowerportions of the eye when viewed in cross-section, said eye interiorfurther including a posterior capsule wall and a second interiorperipheral surface defined between said anterior capsule wall and saidposterior capsule wall, said second interior peripheral surfaceextending circumferentially at said upper and lower portions of the eyewhen viewed in cross-section, said eye further including an optical axispassing through the center of said pupil, the distance between saidfirst interior peripheral surface and the optical axis of said eye beinggreater than the distance between said second interior peripheralsurface and the optical axis of said eye, said insert comprising amedial light focusing lens body having an optical axis and first andsecond opposite peripheral portions, first position fixation meansjoined to said first peripheral portion and having a first seatingportion extending generally radially beyond said first peripheralportion, said first seating portion being engageable with one of saidinterior peripheral surfaces, second position fixation means beingjoined to said second peripheral portion of said lens body and having asecond seating portion extending generally radially beyond said secondperipheral portion, said second seating portion being engageable withthe other said interior peripheral surface to substantially align theoptical axis of said lens body with the optical axis of said eye, saidposition fixation means including means for permitting one of saidseating portions to be resiliently seated at the first interiorperipheral surface of the eye and for permitting the other of saidseating portions to be resiliently seated at the second interiorperipheral surface of the eye.
 2. An intraocular insert as claimed inclaim 1 wherein the seating portion of said one position fixation meanshas a radial extent from the optical axis of said lens body greater by afirst predetermined amount than the radial extent of said first interiorperipheral surface from the optical axis of said eye to permit resilientseating of said one position fixation means, and the seating portion ofthe other said position fixation means has a radial extent from theoptical axis of said lens body greater by a second predetermined amountthan the radial extent of said second interior peripheral surface fromthe optical axis of said eye, to permit resilient seating of said otherposition fixation means.
 3. An intraocular insert as claimed in claim 2wherein the radial extent of said one and said other seating portionsfrom the optical axis of said lens body are substantially equivalent andsaid other position fixation means includes means for permitting agreater magnitude of deflection of its corresponding seating portionthan the magnitude of deflection of the seating portion of said oneposition fixation means in response to a given force on said respectiveseating portions.
 4. An intraocular insert as claimed in claim 3 whereinsaid other position fixation means is formed of a less stiff materialthan said one position fixation means, as the means for permittinggreater deflection of said other position fixation means.
 5. Anintraocular insert as claimed in claim 3 wherein said other positionfixation means is of the same material as said one position fixationmeans but is of lesser cross-section than the first position fixationmeans, as the means for permitting greater deflection.
 6. An intraocularinsert as claimed in claim 2 wherein the radial extent of said oneseating portion from the optical axis of said lens body is greater thanthe radial extent of said other seating portion from the optical axis ofsaid lens body.
 7. An intraocular insert as claimed in claim 6 whereinsaid one and said other seating portions are substantially coplanar. 8.An intraocular insert as claimed in claim 6 wherein one of said positionfixation means is inclined with respect to a plane generally parallel tosaid lens body and containing the other said position fixation means, tooffset the seating portions of said first and said second positionfixation means with respect to each other.
 9. An intraocular insert asclaimed in claim 8 wherein said second position fixation means isinclined with respect to said plane containing said first positionfixation means such that the seating portion of said second positionfixation means is offset forwardly of the seating portion of said firstposition fixation means.
 10. An intraocular insert as claimed in claim 9wherein the offset angle is approximately seven to twelve degrees. 11.An intraocular insert as claimed in claim 6 wherein one of said positionfixation means includes a leg portion having a step formed thereon tooffset the seating portions of said first and said second positionfixation means with respect to each other.
 12. An intraocular insert asclaimed in claim 11 wherein said second position fixation means has saidstepped leg portion such that the seating portions of said secondposition fixation means is offset forwardly of the seating portion ofsaid first position fixation means.
 13. An intraocular insert as claimedin claim 6 wherein said position fixation means are formed of aresilient spring-like plastic such as polypropylene.
 14. An intraocularinsert as claimed in claim 1 wherein one of said position fixation meanscomprises a first J-shaped position fixation member having a first legportion affixed to said one peripheral section of said lens body, thecurved portion of said first J being at the free end of said firstposition fixation member to define the seating portion of said firstposition fixation member.
 15. An intraocular insert as claimed in claim14 wherein the other of said position fixation means comprises a secondJ-shaped position fixation member, having a second leg portion affixedto the other peripheral section of said lens body, the curved portion ofsaid second J being at the free end of said second position fixationmember to define the seating portion of said second position fixationmember.
 16. An intraocular insert as claimed in claim 15 wherein theseating portion of said one position fixation member has a radial extentfrom the optical axis of said lens body greater by a first predeterminedamount than the radial extent of said first interior peripheral surfacefrom the optical axis of said eye to permit resilient seating of saidone position fixation member, and the seating portion of the other saidposition fixation member has a radial extent from the optical axis ofsaid lens body greater by a second predetermined amount than the radialextent of said second interior peripheral surface from the optical axisof said eye to permit resilient seating of said other position fixationmember.
 17. An intraocular insert as claimed in claim 14 wherein theradial extents of said one and said other seating portions from theoptical axis of said lens body are substantially equivalent and saidother position fixation member includes means for permitting a greatermagnitude of deflection of its corresponding seating portion than themagnitude of deflection of the seating portion of said one positionfixation member in response to a given force on said respective seatingportions.
 18. An intraocular insert as claimed in claim 17 wherein saidother position fixation member is formed of a less stiff material thansaid one position fixation member, as the means for permitting greaterdeflection of said other position fixation member.
 19. An intraocularinsert as claimed in claim 17 wherein said other position fixationmember is formed of the same material as said one position fixationmember but is of lesser cross-section than the first position fixationmember, as the means for permitting greater deflection.
 20. Anintraocular insert as claimed in claim 15 wherein the radial extent ofsaid one seating portion from the optical axis of said lens body isgreater than the radial extent of said other seating portion from theoptical axis of said lens body.
 21. An intraocular insert as claimed inclaim 20 wherein said one and said other seating portions aresubstantially coplanar.
 22. An intraocular insert as claimed in claim 20wherein one of said position fixation members is inclined with respectto a plane generally parallel to said lens body and containing the othersaid position fixation member, to offset the seating portions of saidfirst and said second position fixation members with respect to eachother.
 23. An intraocular insert as claimed in claim 20 wherein saidsecond position fixation member is inclined with respect to said planecontaining said first position fixation member such that the seatingportion of said second position fixation member is offset forwardly ofthe seating portion of said first position fixation member.
 24. Anintraocular insert as claimed in claim 23 wherein the offset angle isapproximately seven to twelve degrees.
 25. An intraocular insert asclaimed in claim 20 wherein one of said position fixation membersincludes a leg portion having a step formed thereon to offset theseating portions of said first and said second position fixation memberswith respect to each other.
 26. An intraocular insert as claimed inclaim 25 wherein said second position fixation member has said steppedleg portion such that the seating portion of said second positionfixation member is offset forwardly of the seating portion of said firstposition fixation member.
 27. An intraocular insert as claimed in claim15 wherein the position fixation members are formed of a resilientspring-like plastic such as polypropylene.